1 files changed, 43 insertions, 0 deletions
diff --git a/src/string/strncpy_s.c b/src/string/strncpy_s.c
new file mode 100644
index 00000000..39b045a9
--- /dev/null
+++ b/src/string/strncpy_s.c
@@ -0,0 +1,43 @@
+#include "string.h"
+
+/** copy bounded string **/
+errno_t strncpy_s(char * restrict s1, rsize_t s1max, const char * restrict s2, rsize_t n)
+{
+	__C_EXT(1, 201112L);
+	__ASSERT_NONNULL(s1);
+	__ASSERT_NONNULL(s2);
+	__ASSERT_NOOVERLAP(s1, s2, n);
+
+	size_t i;
+	for (i = 0; i < n; i++) {
+		s1[i] = s2[i];
+		if (s1[i] == '\0') {
+			break;
+		}
+	}
+
+	while (i < n) {
+		s1[i++] = '\0';
+	}
+
+	return s1;
+}
+
+/***
+The fn(strncpy) function copies up to arg(n) bytes from the string at arg(s2)
+to arg(s1). If a char(\0) is encountered, null characters are appended to
+arg(s1) until arg(n) bytes have been written. If no null characters are copied
+in the first arg(n) bytes of arg(s2), the resulting string will not be null
+terminated.
+***/
+
+/* UNSPECIFIED: - */
+/* UNDEFINED: if arg(s1) and arg(s2) overlap */
+/* IMPLEMENTATION: - */
+/* LOCALE: - */
+
+/* RETURN: the value of arg(s1) */
+
+/*
+CEXT1(201112)
+*/